CVE-2021-41750 Cross-site Scripting in SEOmatic plugin

What is CVE-2021-41750?

CVE-2021-41750 is a medium-severity cross-site scripting vulnerability in n/a, published on 12 Jun 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the base64 encoded URL of a malicious web page / file and fileName parameter containing an arbitrary filename with the intended content-type to be rendered in the user's browser as the extension.

Weakness: CWE-79

Which versions are affected by CVE-2021-41750?

2 open source packages ship an affected version, including nystudio107/craft-seomatic. It affects 1 product.

Products include Nystudio107 Seomatic.

How do I fix CVE-2021-41750?

Upgrade nystudio107/craft-seomatic to 3.4.11 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-41750 being exploited?

There is no known exploitation of CVE-2021-41750 in the wild and no public exploit code.

Other vulnerabilities in n/a

• CVE-2021-41749 Code Injection in SEOmatic Critical 9.8
• CVE-2021-44618 Server-side Template Injection in nystudio107/craft-seomatic Critical 9.8
• CVE-2020-12790 SEOmatic for CraftCMS allows Server-Side Template Injection High 7.5
• CVE-2018-14716 SEOmatic plugin for Craft CMS SSTI Vulnerability High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6hjc-m38h-7jhh.